Spiral lowering chute and method of manufacture



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SPIRAL LOWERING CHUTE AND METHOD OFJMANUFACTURE Filed Feb. 21, 1925 3 Sheets-Sheet l.

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Patented 9,

narran i FRANK PARDEE, OF HAZLETN, PENNSYLVAFTA, LSSGNR TQ ANlER-ACTE SEPA- RATOR COMPANY, Ol IAZLETN, FENNSYLVAHA, A CQBERATTON 0F PENNSYL- VAN'IA.

' SPRAL LWERTNG CHUTE .AND TETHGD F MNUFACTURE.

Application filed. February 21, 1925.

rlhis invention relates to spiral lowering chutes adapted for use either as conveyors or separators and to an improved method of manufacturing the same. l,While not limited thereto, the particular embodiment of the invention illustrated is adapted for piling coal.

In the storage of coal it is important that the mass be lowered in such a way that the w lumps are not broken up into smaller sizes, it being well known to those familiar with the coal business, that coal with a minimum of so-called lines commands a higher market value. Coal is frequently stored in bins or in piles in the open and the saine is usually discharged from an overhead car traveling on tracks along the top of a shed or bin. There is often a distance of thirty feet or more between the track level and the floor of the storage. bin or yard.

Spiral lowering chutes have been found to provide a satisfactory means for stacking or piling coal with the minimum breakage and the same have been used by dealers doing a large volume of business. But for the smaller dealer the cost of chutes as heretofore constructed is almost prohibitive. The lowering chutes previously used have been built up by warping flat segmental plates into an approximately spiral or helical shape and joining the plates at their radial edges, such plates forming the flooring of the runway. Tn order to prevent the coal from flying off the outer edge of the runway under the influence of centrifugal force it has heretofore been necessary to provide a sepa 1ate spiral retaining wall or flange following the outline of the edge of the runway.

Tn the manufacture of the previous forms of lowering chutes care must be taken in laying out the segmental pla-tes to form an approximately true spiral, holes must be accurately located for joini g the plates and the side flanges or retaining walls must be carefully formed to follow the line of the runway floor. This all takes time and costs money and while the initial cost of installation does not prohibit the use of the devices by the larger dealers, small concerns find the cost almost prohibitive.

An object of the present invention is provide a method of manufacture and an iink serial no. 10,740.

proved chute of unique construction which can be manufactured and sold at a lower cost than the types heretofore proposed and yet one which will perform its function equally as well. Tn the accompanying drawings Fig. 1 illustrates one embodiment of my improved lowering chute; i

Fig. 2 is an enlarged longitudinal section 60 of the chute shown in Fig. 1;

F 3 is a section on line 3 3 of Fig. 1;

Fig. l is an elevation illustrating a step in the method of forming the runway;

Fig. 5 is a perspective view illustrating a 65 blank from which the spiral may be formed;

Fig. 6 is a detail of a joint between two adjacent sections of the runway.

Fig. 7 is a detail illustrating a modification in the method of forming the runway.

Figs. 8 to 12 show alternative embodiments of the invention. l

Referring in detail to the drawings the lowering chute indicated generally by the numeral 10 is supported by a plurality of up- 75 rights 12 which at spaced intervals are provided with suitable brackets 14 shaped to fit the underside of the runway.

las best shown in Fig. 2 the runway is of concave cross-section. Y The embodiment shown illustrates a runway of substantially semi-circular cross-section the same being so i disposed that the inner edge 18 of the runway is at a considerably lower elevation than the outer edge 20. This disposition of the metal provides a floor portion 22 and what we may terni a side wall portion 24. The coal is fed to the lowering chute from a suitable feed chute indicated at 26 and the material flows by gravity along the spiral floor portion 22 90 and theside wall portion 24 prevents the lumps from dying off on a tangent under the influence of centrifugal force. The runway may be anchored to the uprights in various ways. the drawing illustrating iiush head bolts 28 which pass through suitable holes in the flanges of the uprights 12. Additional securing means may be provided in the form of flush head rivets 8O passing through the runway floor and secured to the brackets 111-. 100

The form of lowering chute above de-y scribed can be manufactured more easily than the types heretofore proposed. This is especially true when they are formed according I utilize a spirally formed piece of pipe or ltubing l0 which is first shaped to the desired pitch and diameter. I then cut away portions of the pipe as indicated at l2 to provide windows or avenues of escape for the coal or other material flowing along` the chute. The cut-outs are made preferably at regular intervals so as to leave reinforcements or connecting ribs 44 which serve to maintain the cross-sectional shape of the pipe.

As indicated in Fig. l2 which is a crosssection on line l2-l2 of F ig. l1, the upper and lower edges 46 and 48, respectively, are located at distances symmetrical with respect to the horizontal center line u-v. In this ligure I have indicated at 50 a cross-section representation of the coal traveling on the runway. It will be noticed that it piles up at an incline which is substantially equal to that of the angle of repose of the coal. The coal travels down the spiral path until it reaches the bottom of the runway where it starts to accumulate on the ground. The following quantities of coal fall over the edge 48 to build up the pile, the latter progressing` from the bottom upwardly as will be understood. Finally, the stacking chute becomes practically imbedded or covered by the coal pile as will be understood from Fig. l. As the coal is used up, of course, the chute is gradually uncovered and when the pile has been consumed the chute can be used again to form another pile. This goes on continuously extending over may be a period of years. Gradually, the portion of the chute over which the coal travels in its spiral trip along the runway, wears away. After this happens the entire runway may be inverted so that the portion which was formerly the top of the runway now becomes the bottom and the coal will be discharged over the edge 46. Thus the life of the lowering chute is practically doubled. y

rThroughout this description I have einphasized the fact that coal or other material being handled is adapted to fall olf the inner edge of the runway. In some forms the edge is continuous as, for example, in Figs. 2 and l() or the discharge edge is interrupted as in Fig. Il. It is not to be inferred, however, that my invention is limited to a conveyor in which the material is discharged inwardly as to the best of my knowledge I am the first tohave proposed making a gravity conveyor by shaping a pipe or tube to spiral form and the invention is intended to embrace a gravity conveyor formed of pipe bentto substantially spiral or helical form and adapted to receive material at the top and to discharge it at the bottom. Such a spiral pipe without apertures or cut away portions is well adapted for lowering coal from one height to another with a minimum breakage of the lumps.

Vhile I have shown upright supports for the spirals in a number of the iigures of the drawings, it is to be understood that in some cases that such supports will be omit-ted inasmuchas the novel form of chute described is of sui'iicient rigidity to be self-supporting. lVhen the uprights are omitted the spiral will be held in place by suitable braces secured to the chute and anchored to the walls of the coal pocket or other adjacent structure.

In the foregoing detailed description the invention has been described as embodied in a spiral lowering chute and the method of manufacturing the same. However, it is to be understood that many of these advantages apply to spiral chutes used for other purposes such, for example, as those used in separating coal from slate and other impurities. The term chute as used in the claims is intended to apply to coal separators as well as to the type of apparatus in which, the chute is merely used to convey material from one point to another.

Though I have described quite specifically certain details of construction and specific steps in the method of producing the runway, it is not to be construed that I am limited thereto as various modifications both in construction and method of manufacture may be resorted to wit-hout departing from the invention as defined in the appended claims.

What I claim is:

l. In the manufacture of spiral chutes, the method which consists in providing a lengt-h of tubing, bending the same to form a spiral of determined pitch and diameter, removing a part of the tube thus leaving a concave chute of the required pitch and diameter.

2. In the manufacture of spiral chutes, the method which consists in providing a straight length of pipe, bending the same to form a spiral of determined pitch and diameter, severing the pipe along substantially parallel lines to form two concave chutes.

3. In the manufacture of spiral chutes, the method which consists in providing a straight length of pipe, bending the same to form a spiral of determined pitch and diameter, severine' the pipe along substantially parallel lines to form two concave chutes, inverting one of the chutes so formed and joining it to an end of the other.

a. In the manufacture of spiral chutes, the method which consists in providing a straight length of pipe, bending the same to form a spiral of determined pitch and diameter, removing a piece from the inner portion of the spiral and dividing the remaining` portion along a substantially spiral line to form. two symmetrical chutes, inverting one of said chutes and joining it to the end of the other to form a continuous spiral runway.

5. A. lowering chute of the class described comprising a runway formed of a plurality of tubular sect-ions bent to spiral form and joined end to end, each section having a outa-wziy portion to pei-init material to fall inwardly Vfrom the runway.

6. A lowering chute of the character described comprising a spi 'al runway Yformed of a plurality of sections joined end to end,

each section comprisingV at pipe segment whose inner Spiral edge is lower than its outer spiral edge. f 10 In witness wl1ereof,l[ have hereunto signed iny naine. i

FRANK PARDEE. 

